func StackArgs(u models.Usercorn) func(n int) ([]uint64, error) {
return func(n int) ([]uint64, error) {
sp, _ := u.RegRead(u.Arch().SP)
// starts with an empty slot
s := u.StrucAt(sp + uint64(u.Bits()/8))
ret := make([]uint64, n)
for i := 0; i < n; i++ {
var arg uint64
var err error
// TODO: simplify this when struc issue #47 is fixed
if u.Bits() == 64 {
err = s.Unpack(&arg)
} else {
var arg32 uint32
err = s.Unpack(&arg32)
arg = uint64(arg32)
}
if err != nil {
return nil, err
}
ret[i] = arg
}
return ret, nil
}
}
func CgcSyscall(u models.Usercorn) {
// TODO: handle errors or something
args, _ := u.ReadRegs(LinuxRegs)
eax, _ := u.RegRead(uc.X86_REG_EAX)
var ret uint64
switch eax {
case 1: // _terminate
syscall.Exit(int(args[0]))
case 2: // transmit
mem, _ := u.MemRead(args[1], args[2])
n, _ := syscall.Write(int(args[0]), mem)
writeAddr(u, args[3], uint64(n))
case 3: // receive
tmp := make([]byte, args[2])
n, _ := syscall.Read(int(args[0]), tmp)
u.MemWrite(args[1], tmp[:n])
writeAddr(u, args[3], uint64(n))
case 5: // allocate
addr, _ := u.Mmap(0, args[0])
// args[1] == is executable
writeAddr(u, args[2], addr)
case 6: // fdwait
nfds := int(args[0])
var readSet, writeSet *fdset32
var timeout posix.Timespec
u.StrucAt(args[1]).Unpack(&readSet)
u.StrucAt(args[2]).Unpack(&writeSet)
u.StrucAt(args[3]).Unpack(&timeout)
readyFds := args[4]
readNative := readSet.Native()
writeNative := writeSet.Native()
n, err := cgcNativeSelect(nfds, readNative, writeNative, &timeout)
if err != nil {
ret = UINT32_MAX // FIXME?
} else {
numReady := int32(n)
if readyFds != 0 {
u.StrucAt(readyFds).Pack(numReady)
}
}
case 7: // random
tmp := make([]byte, args[1])
rand.Read(tmp)
u.MemWrite(args[0], tmp)
writeAddr(u, args[2], args[1])
}
u.RegWrite(uc.X86_REG_EAX, ret)
}
func NewBuf(u models.Usercorn, addr uint64) Buf {
return Buf{U: u, Addr: addr, StrucStream: u.StrucAt(addr)}
}